admob app status changed to inactive

I have new app that uses Admob. It was showing up as active a few days ago. But all of a sudden now the status is back to inactive.

On my test device I get the test ad, but if I turn off the addTestDevice() line, I get no advert at all, and I get this in logcat:

onFailedToReceiveAd(Ad request successful, but no ad returned due to lack of ad inventory.)

I quess my app was blocked due to high maturity content, any way to contact admob to clarify this?